Longitudinally adjustable drill boom



11, 1970 E. v. KIMBER 3,523,336

LONGITUDINALLY ADJUSTABLE DRILL BOOM Filed May 21. 1968 2 Sheets-Sheet lINVENTOR.

970 E. v. KIMBER 3,523,336

LONGITUDINALLY ADJUSTABLE DRILL BOOM Filed May 21. 1968 2 Sheets-Sheet 2g 7 Arrcz K Za Zi- 3 z ZMuQ/ United States Patent 01 :"fice 3,523,336Patented Aug. 11, 1970 3,523,336 LONGITUDINALLY ADJUSTABLE DRHL BOOMErich Valdemar Kimber, Vendelso, Sweden, assignor to Atlas CopcoAktiebolag, Nacka, Sweden, a corporation of Sweden Filed May 21, 1968,Ser. No. 730,717 Claims priority, application Sweden, May 24, 1967,7,262/ 67 Int. Cl. E21c 11/00 US. Cl. 24-16 9 Claims ABSTRACT OF THEDISCLOSURE A drill boom is longitudinally extensible and contractible bya power cylinder. The drill boom extension mechanism includes a boomextension member longitudinally v This invention relates to drill boomsand more particularly to longitudinally adjustable drill booms adaptedfor positioning a drilling apparatus to different alternative drillingpositions with respect to a work surface. Drill booms are normallysubjected to fluxural stress under the influence of their own weight andof feeding forces causing considerable deflection of the end of the boomvertically or in a transverse plane defined by the drilling direction.During deflection of conventional booms of the longitudinally extensibletype there is usually the risk of elongated parts of the boom extensionmechanism becoming stuck in the journal bearing and guides thereof sothat the latter may be deformed permanently to suchan extent that thelongitudinal adjusting function is imperiled. A constructionalreinforcement of the elements and guides of the goom extension mechanismdoes not result in a satisfactory solution here because of theundesirable increase in weight. It is therefore an object of theinvention to provide an improved boom extension mechanism for alongitudinally adjustable drill boom which mechanism during deflectingload on the drill boom is relieved from deformations to such an extentthat sticking is entirely avoided. Another object of the invention is tocreate simultaneously herewith a constructional solution presenting alow'total weight for the elements included in the boom extensionmechanism.

For these and other purposes there is according to the inventionprovided a longitudinally adjustable drill boom adapted for positioninga rock drilling apparatus to different alternative drilling positionswith respect to a work surface and comprising a boom support, a hollowdrill boom swingably mounted at the inner end thereof on said boomsupport, a journal bearing at the outer end of said drill boom, anadjusting head having a boom extension member thereon received in saidjournal bearing for slidably supporting said adjusting head thereon, adrilling apparatus adjustably supported on said adjusting head, a powercylinder connected to said drill boom and to said adjusting head foradjusting the length of said drill boom between said adjusting head andsaid boom support, a guiding sleeve afiixed to the outer end of thedrill boom and extending into the interior of the drill boom around saidboom extension member, means for guiding the inner end portion of saidboom extension member longitudinally slidably in said guiding sleeve,and said guiding sleeve having such clearance peripherally therearoundin said drill boom as to avoid deformation of said guiding sleeveagainst interior parts of said drill boom during normal deflection ofthe latter. As a result of the chosen solution the entire sleeve willfollow the angular movements of the end of the boom during deflectionand will stay straight so that sticking of the boom extension member isavoided.

The above and other objects of the invention will become obvious fromthe following description and from the accompanying drawings in which apreferred embodiment of the invention is illustrated by way of example.It should be understood that this embodiment is only illustrative of theinvention and that various modifications thereof may be made within thescope of the claims.

In the drawings FIG. 1 shows a diagrammatic side view of a drill boomtogether with a drilling apparatus carried thereby, an extended positionof the drill boom being indicated by broken lines. FIG. 2 shows anenlarged fragmentary vertical section through the inner end of drillboom in FIG. 1. FIG. 3 is a cross section through the drill boom on theline 33 in FIG. 2. FIG. 4 shows on the same scale as FIG. 2 afragmentary vertical section through the outer end of the drill boom.FIG. 5 is a cross section on the line 5-5 in FIG. 4. FIG. 6 is a crosssection on the line 66 in FIG. 4. FIG. 7 finally shows a partlysectional side view of a guiding sleeve also shown in FIGS. 2 and 4 andintended for receiving therein the the boom extension member of thedrill boom.

In FIG. 1 the drill boom 10 is supported at the inner end thereofvertically and laterally pivotally about suitable axles on aconventional boom support 12 which is affixed to an element 13 formingpart of a drill wagon or rig, not shown. The elevation and side swingangles of the drill boom are set by means of conventional hydrauliccylinders journalled on the boom support 12. The drill boom 10 carriesat the outer end thereof an adjusting head 14 for mechanized orientationof a drilling apparatus including a feed shell 16 provided with a rockdrill 15 and a power feed thereon for the rock drill 15. Furthermorethere are supported conventional hydraulic cylinders, not shown indetail, on the adjusting head 14 for purposes of positioning saiddrilling apparatus.

The adjusting head 14 includes a fork 11 as a carrying member which isfixed by screws to a cylindrical hollow boom extension member 17. Theboom extension member 17 is slidably guided in a journal bearing 18 atthe outer end of the drill boom 10. The latter is made with a hollowstraight jib portion 10 which is quadrangular in cross section and intothe interior of which the boom extension member 17 projects. The jibportion 10 is pivotally journalled on the boom support 12 by an angulararm 10 extending upwardly and angularly outwardly from the upper sideside of the jib portion 10 Between the folk 11 and an outer flange onthe boom extension member 17 is bolted an intermediate piece 19extending into the boom extension member 17 from the forward endthereof. The intermediate piece 19 carries journalling lugs 20 at theinner end thereof. A pivot 21 is carried by the journalling lugs 20which pivot 21 at the middle portion thereof is provided with a ring 22having a spherical bearing surface, FIG. 5.

The jib portion 10 of the drill boom 10 carries flanges 23 at the outerend thereof and flanges 24 at the inner end thereof. The journal bearing18 is supported by an outer portion of a tubular guiding sleeve 25 whichby means of a flange 32 is affixed to the flanges 23 together with acover ring 26 slidably surrounding the boom extension member 17 and acentering ring 27. The guiding sleeve 25 extends far into the interiorof the jib portion 10 and has a considerable radial spacing or clearance43 peripherally therearound with respect to the inner walls of the jibportion 10 The guiding sleeve 25 is provided with a pair ofdiametrically arranged guideways or guiding grooves 28 which extendalong the major portion of the length thereof. In the guiding grooves 28is nonrotatably slidable a pair of guides or wedges 29 which areinserted in recesses 30 at the inner end of the boom extension member 17and bolted to the latter. In connection with the grooves 28 in theguiding sleeve 25 there are arranged openings 31, FIG. 7, for insertingthe wedges 29 during assembly. The wedges 29 are surrounding by slideplates 45 of bronze filling the radial play between the guiding sleeve25 and the boom extension member 17 and providing a journal for theinner end of the latter whereby said inner end is supportedlongitudinally slidably in the drill boom.

The inner end of the journal bearing 18 is supported by a peripheralsupport member 32 which is fixed to the inside of the jib portion 10 atsome distance from the flange 32, FIG. 4. To the inner flanges 24 of thejib portion 10 is aflixed a bracket or a cover 33 which carries innerjournalling lugs 34. Between the journalling lugs 34 is seated a pivot35 on which a piston rod 36 is journalled. The piston 36 is included ina preferably bydraulically actuated power cylinder 37. The operatingconduits 39, 40 of the power cylinder 37 are led through the cover 33 tothe piston rod 36. The piston rod 36 is made hollow and carriescentrally therein an inner tube 38. The conduits 39, 40 communicaterespectively via the piston rod 36 and via the inner tube 38 with theopposite ends of a piston 44 slidably and sealingly guided in thecylinder 37. By alternate supply and draining of pressure fluid to andfrom the conduits 39, 40, the working chambers of the cylinder 37 canalternately be pressurized so that the cylinder 37 is displaced withinthe jib portion 10 in a direction away from or towards the pivot 35. Theouter end of the cylinder 37 carries a lug 41 thereon in which isinserted a spherically recessed bearing ring 42, FIG. 5, cooperatingwith the spherical ring 22 on the pivot 21.

Displacement of the cylinder 37 outwardly or inwardly in the jib portion:10 is transmitted via the pivot 21 to the intermediate piece 19 and theadjusting head 14 so that the boom extension member 17 is caused toslide outwardly or inwardly in the journal bearing 18 for example fromthe position shown by full lines in FIG. 1 to the position 14 -16depicted by broken lines therein or to some position therebetween.Rotation of the boom extension member 17 is prevented by the guides orwedges 229 sliding in the grooves 28 whereby the latter provideguideways for the wedges 29. During such longitudinal adjustment theboom extension member 17 is always rigidly supported in the journalbearing 18 and by the sliding plates 45. Because of the Weight of thedrilling apparatus 15, 16 and the adjusting head 14 and also duringaction of feed reaction forces against the feed shell 16 the drill boom10 is deflected. Since the guiding sleeve 25 takes part in the angularmovement caused by the deflection at the outer end of the drill boom 10and since the clearance 43 will be chosen so large that the innerportion of the guiding sleeve 25 during normal deflection will not bedeformed by contacting theinner walls of the jib portion 10 FIG. 2,permanent deform tion and sticking of the elements within the drill boomis avoided. Simultaneously there is received a lightweight and simpleboom design which makes possible the use of a power cylinder 37 ofstandard make and is suitable for providing the basic unit of a boomcomponent system which may be combined in a rational way for providingvarious functions.

During drilling the spherical ring connection 22, 42 on the pivot 21,FIG. 5, as well as the pivot 21 make possible limited pivotal movementin two planes perpendicular to one another. This permits limiteduniversal angular movability in any direction between the intermediatepiece 19 and adjusting head 14 on the one hand and the power cylinder 37on the other. Thanks to this the cylinder 37 can freely adapt itself todeflections of the outer end of the drill boom 10.

What I claim is:

1. A longitudinally adjustable drill boom adapted for positioning a rockdrilling apparatus to different alternative drilling positions withrespect to a work surface and comprising a boom support, a hollow drillboom swingably mounted at the inner end thereof on said boom support, ajournal bearing at the outer end of said drill boom, an adjusting headhaving a boom extension member thereon received in said journal bearingfor slidably supporting said adjusting head thereon, a drillingapparatus adjustably supported on said adjusting head, a power cylinderconnected to said drill boom and to said adjusting head for adjustingthe length of said drill boom between said adjusting head and said boomsupport, a guiding sleeve aflixed to the outer end of the drill boom andextending into the interior of the drill boom around said boom extensionmember, means for guiding the inner end portion of said boom extensionmember longitudinally slidably in said guiding sleeve, and said guidingsleeve having such clearance peripherally therearound in said drill boomas to avoid deformation of said guiding sleeve against interior parts ofsaid drill boom during normal deflection of the latter.

2. A drill boom according to claim 1 in which there are providedlongitudinal guideways on said guide sleeve, and cooperating guides atthe inner end of said boom extension member in axially slidableengagement with said guideways for guiding said boom extension membernonrotatably during longitudinal sliding movement thereof in saidguiding sleeve.

3. A drill boom according to claim 1 in which said drill boom has flangemeans at the outer end thereof and said journal bearing is made as anelongated tubular member in one piece with said guiding sleeve and isafiixed to said flange means.

4. A drill boom according to claim 1 in which said boom extension memberis hollow and said power cylinder is mounted in said boom extensionmember with one end thereof connected to said adjusting head and theother to said drill boom.

5. A drill boom according to claim 4 in which the connection betweensaid one end of said power cylinder and said adjusting head includespivot means in two planes perpendicular to one another for permittinguniversal angular adaptability between said power cylinder and saidhead.

6. A drill boom according to claim 1 in which said drill boom isprovided with inner and outer flanges respectively at the inner andouter end thereof, a through cavity in said drill boom between saidflanges, said journal bearing and guiding sleeve being made in one pieceas an elongated tubular member aflixed to said outer flanges andextending into said cavity, a bracket connected to the inner flanges ofsaid drill boom, and said power cylinder being mounted within said boomextension member with one end thereof connected to said boom extensionmember and adjusting head and the other to said bracket.

7. In an extensible and contractible drill boom an elongated hollow jibportion having flanges at the opposed ends thereof and a through cavitystraightly therebetween, a tubular elongated guiding sleeve extendinginto said jib portion and being connected to the flanges at one end ofsaid jib portion, a bracket connected to the flanges at the other end ofsaid jibportion, a journal bearing in said guiding sleeve at the endthereof connected to said jib portion, an elongated hollow boomextension member longitudinally slidably guided in said guide sleeve aswell as in said journal bearing, a power cylinder in said boom extensionmember connected therebetween said bracket for longitudinal adjustmentof said boom extension member relative to said jib portion, and saidguiding sleeve having such clearance peripherally therearound in saidjib portion as to avoid deformation of said guiding sleeve againstinterior parts of said jib portion during normal deflection of thelatter.

8. In a drill boom according to claim 7 longitudinal grooves on saidguide sleeve, and wedges affixed to said boom extension member and inaxially slidable engagement with said grooves for guiding said boomextension member non-rotatably during longitudinal sliding movementthereof in said guiding sleeve.

9. In a drill boom according to claim 7 the connection between saidpower cylinder and said boom extension member including pivot means intwo planes perpendicular to one another for permitting universal angularadaptability between said power cylinder and said boom extension member.

References Cited UNITED STATES PATENTS 3,212,604 10/1965 Garnett l822 X3,260,374 7/1966 Haganes 2l2144 X 3,354,967 11/1967 Skendrovic 17343 ROYD. FRAZIER, Primary Examiner J. F. FOSS, Assistant Examiner US. Cl. X.R.

